Accelerator based neutron generators have a wide variety of applications including medicine, security, and oil and gas exploration. Accelerator based neutron generators extract ions produced at an ion source and accelerate them through an accelerator tube towards a target where collisions produce fusion reactions that yield neutrons. Some accelerator based neutron generators utilize radio frequency (RF) driven plasma ion sources. Some such RF driven plasma sources rely on coupling RF energy produced by an RF antenna into the plasma source to drive plasma production.